Publications

Pleistocene basalt of the Mount Edgecumbe volcanic field (MEF) is subdivided into a plagioclase type and an olivine type. Olivine basalt crops out farther inboard from the nearby Fairweather transform than plagioclase basalt. Th/La ratios of plagioclase basalt are similar to those of mid-ocean-ridge basalt (MORB), whereas those of olivine basalt are of continental affinity. The olivine...

Inflated pahoehoe sheet flows have a distinctive horizontal upper surface, which can be several hundred meters across, and are bounded to steep monoclinal uplifts. The inflated sheet flows studied ranged from 1 to 5 m in thickness, but initially propagated as thin sheets of fluid pahoehoe lava, generally 20-30 cm thick. The morphology of the lava as flow advanced is described. Inflated...

No abstract available

Currently, gas emissions from Kilauea occur from the summit caldera, along the middle East Rift Zone (ERZ), and where lava enters the ocean. We estimate that the current ERZ eruption of Kilauea releases between 400 metric tonnes of SO2 per day, during eruptive pauses, to as much as 1850 metric tonnes per day during actively erupting periods, along with lesser amounts of other chemically...

As part of a hazards-assessment study, we examined the nature and rate of geomorphic change caused by outburst floods and debris flows along Tahoma Creek. Mount Rainier, since 1967. Archival aerial photographs of the area proved to be a rich source of qualitative geomorphic information. On the basis of limited direct evidence and considerations of stream hydrology, we conclude that...

T he Earth is a bountiful source of heat. It continuously produces heat at depth, primarily by the decay of naturally radioactive chemical elements (principally uranium, thorium, and potassium) that occur in small amounts in all rocks. This deep heat then rises toward the cooler surface, where scientists can measure the rate of its escape through the Earth's crust. The annual heat loss...

In 1990, the State of Hawaii proposed the Hawaii Geothermal Project for the development of as much as 500 MW of electric power from the geothermal system in the East Rift Zone of Kilauea Volcano. This report uses data from 31 wells and 8 springs to describe the properties of the ground-water system in and adjacent to the East Rift Zone. Potential effects of this project on ground-water...

The December 1989–June 1990 eruption of Redoubt Volcano affected commercial and military air operations in the vicinity of Anchorage, Alaska. These effects were due to the direct impact of volcanic ash on jet aircraft, as well as to the rerouting and cancellations of flight operations owing to eruptive activity. Between December and February, five commercial jetliners were damaged from...

Trace-element abundances were measured in situ by ion microprobe in five samples of hornblende and melt ranging from basaltic andesite to high-silica rhyolite. Except for one sample, for which quench overgrowth or disequilibrium is suspected, the abundance ratios show systematic inter-element and inter-sample variations, and probably approach true partition coefficients. Apparent...

Opaline sinter samples collected at Yellowstone National Park (YNP) were analyzed for gold by neutron activation and for other trace elements by the inductively coupled plasma optical emission spectroscopy (ICP-OES) method. No correlation was found between Au and As, Sb, or total Fe in the sinters, although the sample containing the highest Au also contains the highest Sb. There also was...

[No abstract available]

Aftershocks of large earthquakes tend to occur close to the main rupture zone, and can be used to constrain its dimensions. But following the 1992 Landers earthquake (magnitude M(w) = 7.3) in southern California, many aftershocks were reported in areas remote from the mainshock. Intriguingly, this remote seismicity occurred in small clusters near active volcanic and geothermal systems...